When should I stop building links on the same IP

Been started my PBN experiment and currently I'm building links manually only to one of my website to test them. In total I've got like 10 sites for starts (wordpress, blogspot, tumblr)

Currently I've done like 50 links (forum comment, profile, web 2.0) to boost my site. All of them were done by the same IP, different emails (like 4-5 in total). The platforms are totally different, didn't do two links on the same platform/site.

I'm safe?
I personally don't think its a problem to build links on the same IP if the platforms are different but speaking of that.

• How many platforms (like wordpress, tumblr, blogspot sites) can I manage on the same IP without leaving any heavy footprints or risking being penalized in the future?
• For managing like 3 sites on each platform is enough to just use different emails or do I need proxies?
• And for blog comments, link profiles same question, is enough to only use different emails? or do I need to change my IP for every comment I leave for example
• For these kind of actions do I need high quality proxies or bulk one can work too?

I can't suggest i switch ip whenever i feel like.

I guess there is no any problem to use the same IP as long as you are making backlinks on different websites. But for suggestion I will suggest you to use mozila Firefox instead of google chrome because chrome is made by Google and I guess they can track your backlink creating activity.

you are and will be safe!

building backlinks in one PC/IP would not the reason which makes Google penalize your site as they don't own the data of these platforms you built your backlinks in.
it would be safer if you built your backlinks in other web browsers (firefox, opera, safari...) instead of Google Chrome and use private/anonymous web browser as well.